For the storage of excess energy which is generated, for example, during the operation of renewable energy sources and which cannot be taken up by the power system, rechargeable oxide batteries (ROB) offer a good possibility for storing relatively large quantities of energy.
What the ROBs have in common is that an energy storage medium is needed in order to fulfill a plurality of physical parameters. Said parameters include, in particular, a large number of charging and discharging cycles, wherein it has been found that the porosity of the storage medium, in particular, as well as the mechanical stability thereof are essential criteria. At present, loose powders or slicks or pre-sintered moldings made of a metal oxide are used as storage media. Although, using said storage media, it is possible to achieve a high level of loading of the cells with the energy storage medium, the disadvantage of all previously known embodiments of the storage medium lies, in particular, in the fact that over a large number of charging and discharging cycles, the porosity decreases because, due to the temperature loading, the metal particles become sintered or fused together. As the number of cycles increases, an ageing process therefore occurs in the energy storage unit, which forces an early replacement of the unit.